NEW YORK (Reuters) - CVS Corp’s proposed purchase of Aetna Inc will affect decision-making by a majority of large and mid-size U.S. corporations on employee health benefits, a survey by benefits consultant Aon Plc found.

Logos of CVS and Aetna are displayed on a monitor above the floor of the New York Stock Exchange shortly after the opening bell in New York, U.S., December 5, 2017. REUTERS/Lucas Jackson

CVS, the second-largest U.S. pharmacy benefit manager, on Dec. 3 said it agreed to buy No. 3 health insurer Aetna for $69 billion. Reuters reported earlier this month that the deal would change the way top U.S. employers contract health benefits, based on early feedback from benefits consultants.

The new Aon survey, which included responses from decision makers at 450 medium and large-size corporations, provided additional insight into how CVS and Aetna customers may view the deal.

Sixty-one percent of survey respondents, including ones that are not customers of CVS or Aetna, said the deal would affect their decision-making process on health benefits, with 23 percent saying it would accelerate a reassessment of healthcare strategy and 38 percent saying it would delay any such moves until the transaction’s impact could be understood.

Thirty-nine percent expected no change to their overall healthcare strategy. The survey did not determine whether major employers expect the deal to change the cost of their health benefits, which could affect how antitrust regulators view it.

A majority of large employers contract with separate companies to provide prescription drug coverage and medical coverage, believing they can keep costs lower in that way. Combining CVS with Aetna would leave only one major pharmacy benefits company, Express Scripts Holding Co, operating as a standalone entity. CVS and Aetna argue they can offer bigger savings to customers by better managing prescription drug use and expanding lower-cost medical services offered at thousands of CVS pharmacies.

Jim Winkler, Aon senior vice president for health, said he was surprised that as many companies thought they might make a change in their overall healthcare strategy, whether immediately or down the road.

“This is on their radar screen in a bigger way than I would have anticipated,” Winkler said. “Typically employers tend to look at this type of news and think ‘it’s too big, and it’s too far off to matter to me yet.’”

The Aon survey was conducted during an online seminar with corporate decision makers on Thursday. Many participants focused their questions on what kinds of medical services CVS might introduce in its pharmacies, Winkler said. According to the survey, 71 percent of respondents expect moderate changes in where their employees access care, while 14 percent said they foresee significant changes.

Among a smaller group of 210 respondents, 52 percent surveyed by Aon said they planned to keep their pharmacy benefits separate from medical coverage. An additional 15 percent said they are considering separating those contracts.